alien_0 = {'color': 'green', 'points': 5, }
print(alien_0['color'])
print(alien_0['points'])

alien_0 = {}
alien_0['x_position'] = 0
alien_0['y_position'] = 25
print(alien_0)
alien_0['y_position'] = alien_0['y_position'] + 5
print(alien_0)
del alien_0['y_position']
print(alien_0)

user_0 = {
    'username': 'efermi',
    'first': 'enrico',
    'last': 'fermi',
}
for key, value in user_0.items():
    print("key: " + key)
    print("value: " + value)

favorite_languages = {
    'jen': 'python',
    'sarah': 'c',
    'edward': 'ruby',
    'phil': 'python',
}
print("------- iter keys ------")
for key in favorite_languages.keys():
    print("key: " + key.title())

print("------- iter keys sorted ------")
for key in sorted(favorite_languages.keys()):
    print("key: " + key.title())

print("------- iter values without duplication ------")
for language in set(favorite_languages.values()):
    print("language: " + language.title())
